Conformational fluctuations in anthrax protective antigen: a possible role of calcium in the folding pathway of the protein

FEBS Letters

Chowdhury, Shantanu¹  Maithal, Kapil²  Kurupati, Raj K²  Gaur, Reetika²  Chandra, Harish¹  Tandon, Vibha²  Gupta, Pradeep K²  Singh, Yogendra¹ 

[1] Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India;Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India

关键词: Anthrax toxin;    Protective antigen;    Calcium;    Proteolysis;    Denaturation;    Folding pathway;   

DOI  :  10.1016/S0014-5793(03)01226-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Protective antigen (PA) is the central receptor binding component of anthrax toxin, which translocates catalytic components of the toxin into the cytosol of mammalian cells. Ever since the crystal structure of PA was solved, there have been speculations regarding the possible role of calcium ions present in domain I of the protein. We have carried out a systematic study to elucidate the effect of calcium removal on the structural stability of PA using various optical spectroscopic techniques, limited proteolysis and mutational analysis. Urea denaturation studies clearly suggest that the unfolding pathway of the protein follows a non-two state transition with apo-PA being an intermediate species, whereas the folding pathway shows that calcium ions may be critical for the initial protein assembly.

【 授权许可】

Unknown